You'd think, after 125 years, that the simple bicycle wouldn't have many radical new ideas left. Well, the glacial pace of change on two wheels is a thing of the past. The 2014 models showcase at least four huge and practical changes: mountain-bike-style braking that has broken into road bikes, new and improved mountain-bike wheel sizes, built-in lighting for commuter bikes, and even extra water and tool-storage capacity for mountain bikes. It's just too bad you can't get them all on one bike.

Roadie disc brakes

Cannondale Synapse Disc 5: Moderate-priced, aluminum-framed road bike with the next big thing: disc brakes, which have better stopping power than traditional rim brakes (that clamp on the rim). Cannondale is not the first with road discs, but it's more proof that they are inevitable. Two other Synapse models, the $2,170 Disc 3 and the $9,000 carbon-framed Hi-Mod with electronic shifting, also have them.

Likes: The exhilaration of being safe at high speeds. It's a giddy thrill to go from a sprint to a dead stop in half the normal distance. You become a better rider knowing you can slow down and stop so much quicker. I found myself flying in and out of corners way faster than usual, as if I suddenly grew more powerful quads — or more hair on my chest. It was an amazing sense of déjà vu — the same feeling I got with my first disc-braked mountain bike a dozen years ago. A great all-round package, the Disc 5 includes the mid-range Shimano 105 20-speed drive train and a comfortable "endurance" design with slightly longer wheelbase and taller handlebars than a classic race bike, some subtle shock-absorption from flattened tubes in the frame and carbon fork and the seat post, and super-wide bottom bracket for good power transfer. It also has rear mounts for racks and fenders, and spacing for wider tires, giving it some versatility for gravel roads.

Dislikes: Disc brakes aren't yet approved for official racing and weigh a bit more than rim brakes.

Giant Trance 27.5 No. 1: Aluminum-framed full-suspension mountain trail bike with 27.5-inch diameter tires, which suddenly this year have emerged as the go-to, do-it-all tire size across the industry. In theory, 27.5-inch tires deliver most of the advantages of the traditional 26-inch wheels (quick handling and acceleration with light weight) and the newer 29-inch versions (high-speed, roll-over-anything capability, low center of gravity) with few of the drawbacks. Of all the major brands, Giant committed most to 27.5-inch tires, with 40 new models and a line of aluminum and carbon Trances ranging from $2,125 to $7,725.

Likes: This thing just feels right — the sweet spot of agility, balance, speed and weight. I've ridden and raved about 29-inch versions for a dozen years, but the superb maneuverability and rollover of the 27.5-inch size was stunning. It definitely seemed faster on technical trails — almost enough to make me forget the slight drop in raw speed on easy terrain. Combined with 5.5 inches (140 millimeters) of rear suspension, an adjustable 120-140 mm fork, a great floating-pivot suspension design, a handy handlebar-actuated dropper seat post and 22-speed Shimano XT drive train, the double chain-ring Trance is an aggressive, high-performance monster. It's pretty too; brushed aluminum with aqua accents and clean internal cable routing.

Specialized Epic Comp 29er: The low-end model of the only dual-suspension mountain bike line that can hold two water bottles and a tool pouch within the main frame area, eliminating the need for a hydration backpack on shorter rides. All Epic models use fast-rolling 29-inch tires; they range from this aluminum-framed bike to the $10,500 ultra-light carbon World Cup model.

Likes: Very convenient storage of water and tools — plus a 29er's great speed and blast-over-anything qualities. Being able to carry two water bottles means you can leave your pack at home for short rides or lug more water on long rides. Also unique to the Epic is a plastic SWAT (storage, water, air and tools) box under the front bottle; it holds a spare tube, a tire lever, a CO2 inflator and a cartridge. Also, the bike has a hidden mini-tool incorporated into the top tube, and a chain tool and a spare link hidden under the headset's cap. Cables are hidden for a clean look. The Epic Comp includes a 20-speed SRAM X9 drive train, 100 mm of suspension travel, a simplified suspension setup called Auto Sag, while the Epic Comp Carbon ($4,200) uses a 20-speed Shimano XT.

Dislikes: The special SWAT cages, tool box and tools must be purchased separately on the Carbon Comp and Epic Comp.

Devinci Newton: 20-speed, eco-friendly aluminum-framed commuter bike with the bike world's only built-in, battery-free lights. The front and rear lights, on the fork and the frame, respectively, are powered by a generator built into the front wheel's hub.

Likes: It's about time. Cars come with lights, so why not bikes? Sleek-looking, safe and practical, this commuter has front and rear lights that keep flashing at all times, day and night. Reflective tires and paint assure that you're visible from every angle. The lights continue blinking for up to 90 seconds after you're stopped at a light. A fork stopper prevents the handlebars from spinning completely around, protecting the paint and the internal wiring from damage. It includes disc brakes, partial internal routing for a very clean look and subtle rack/fender mounts.